var phoneWidth = parseInt(window.screen.width);
var phoneScale = phoneWidth / 750;
var ua = navigator.userAgent;
if (/Android (\d+\.\d+)/.test(ua)) {
    var version = parseFloat(RegExp.$1);
    // andriod 2.3
    if (version > 2.3) {
        document.write('<meta name="viewport" content="width=750, minimum-scale = ' + phoneScale + ', maximum-scale = ' + phoneScale + ', viewport-fit=cover">');
        // andriod 2.3以上
    } else {
        document.write('<meta name="viewport" content="width=750, viewport-fit=cover">');
    }
    // 其他系统
} else {
    document.write('<meta name="viewport" content="width=750, user-scalable=no, viewport-fit=cover">');
}
//微信去掉下方刷新栏
if (RegExp("MicroMessenger").test(navigator.userAgent)) {
    document.addEventListener('WeixinJSBridgeReady', function onBridgeReady() {
        WeixinJSBridge.call('hideToolbar');
    });
}